The speed of propagation of the pulse wave is a parameter which permits an assessment of the physical state of the arteries through which said wave is propagated, with a view to estimating the cardiovascular risk in a subject. The risk of cardiovascular accident can result in particular in the following risks for the organs of the subject:                the heart: angina pectoris, infarction        the brain: cerebral haemorrhage or ischaemia;        the kidney: renal failure;        the aorta: aneurysm, dissection.        
Methods are known from the prior art for determining the speed of propagation of the pulse wave, which are used to determine a pulse wave index, as a function of the pulse wave velocity measured between the heart and a finger, and of the pulse wave velocity measured between the heart and a toe. Such a method is described in the patent application published under number FR2947167 and allows a possible cardiovascular risk to be determined.
To further improve the determining of risks linked to arterial stiffness, it is desirable to be able to use another method and another corresponding apparatus, i.e. an alternative method and apparatus to the solution known from the prior art, whilst maintaining a reliability and a repeatability of the measurements.